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Kommunikatsiooniteenuste arendus IRT0080

Kommunikatsiooniteenuste arendus IRT0080. Loeng 12, “ IP v6 + QoS” Avo Ots telekommunikatsiooni õppetool, TTÜ raadio- ja sidetehnika inst. avo.ots@ttu.ee. IPv6. Redefine functions of IP (version 4) What changes should be made in…. IP addressing IP delivery semantics IP quality of service

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Kommunikatsiooniteenuste arendus IRT0080

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  1. Kommunikatsiooniteenuste arendusIRT0080 Loeng 12, “ IP v6 + QoS”Avo Otstelekommunikatsiooni õppetool, TTÜ raadio- ja sidetehnika inst.avo.ots@ttu.ee

  2. IPv6 • Redefine functions of IP (version 4) • What changes should be made in…. • IP addressing • IP delivery semantics • IP quality of service • IP security • IP routing • IP fragmentation • IP error detection

  3. IPv6 • Initial motivation:32-bit address space soon to be completely allocated (est. 2008) • Additional motivation: • Remove ancillary functionality • header format helps speed processing/forwarding • Add missing, but essential functionality • header changes to facilitate QoS • new “anycast” address: route to “best” of several replicated servers IPv6 datagram format: • fixed-length 40 byte header • no fragmentation allowed

  4. IPv6 Header (Cont) Priority: identify priority among datagrams in flow Flow Label: identify datagrams in same “flow.” (concept of“flow” not well defined). Next header: identify upper layer protocol for data

  5. IPv6 Changes • Scale – addresses are 128bit • Header size? • Simplification • Removes infrequently used parts of header • 40 byte fixed header vs. 20+ byte variable header • IPv6 removes checksum • IPv4 checksum = provide extra protection on top of data-link layer and below transport layer • End-to-end principle • Is this necessary? • IPv6 answer =>No • Relies on upper layer protocols to provide integrity • Reduces processing time at each hop

  6. IPv6 Changes • IPv6 eliminates fragmentation • Requires path MTU discovery • ICMPv6: new version of ICMP • additional message types, e.g. “Packet Too Big” • multicast group management functions • Protocol field replaced by next header field • Unify support for protocol demultiplexing as well as option processing • Option processing • Options allowed, but only outside of header, indicated by “Next Header” field • Options header does not need to be processed by every router • Large performance improvement • Makes options practical/useful

  7. IPv6 Changes • TOS replaced with traffic class octet • Support QoS via DiffServ • FlowID field • Help soft state systems, accelerate flow classification • Maps well onto TCP connection or stream of UDP packets on host-port pair • Easy configuration • Provides auto-configuration using hardware MAC address • Additional requirements • Support for security • Support for mobility

  8. Transition From IPv4 To IPv6 • Not all routers can be upgraded simultaneous • no “flag days” • How will the network operate with mixed IPv4 and IPv6 routers? • Two proposed approaches: • Dual Stack: some routers with dual stack (v6, v4) can “translate” between formats • Tunneling: IPv6 carried as payload in an IPv4 datagram among IPv4 routers

  9. A B E F F E B A tunnel Logical view: IPv6 IPv6 IPv6 IPv6 Physical view: IPv6 IPv6 IPv6 IPv6 IPv4 IPv4 Tunneling

  10. Flow: X Src: A Dest: F data Flow: X Src: A Dest: F data Flow: X Src: A Dest: F data Flow: X Src: A Dest: F data D C F E B A F E B A Src:B Dest: E Src:B Dest: E Tunneling tunnel Logical view: IPv6 IPv6 IPv6 IPv6 Physical view: IPv6 IPv6 IPv6 IPv6 IPv4 IPv4 A-to-B: IPv6 E-to-F: IPv6 B-to-C: IPv6 inside IPv4 B-to-C: IPv6 inside IPv4

  11. Dual Stack Approach • Dual-stack router translates b/w v4 and v6 • v4 addresses have special v6 equivalents • Issue: how to translate “FlowField” of v6 ?

  12. QoS • Pakettvõrkudes liikluse korralduse (traffic engineering) mõiste “garanteeritud teenuse kvaliteet” (QoS, Quality of Service) tähendab tõenäosuslikku hinnangut, et sidevõrk jälgib liikluslepet. • Paljudel juhtudel kasutatakse QoS tõenäosusena, et pakett läbib võrku saatjast vastuvõtjani oma ettemääratud ajavahemiku jooksul.

  13. Teenusekvaliteedi aspektid QoS – Quality of Service ITU-T E.800 Recommendation

  14. Teenusekvaliteedi aspektid (2) QoS Teenuse Kättesaadavus (Accessibility) Teenuse Püsivus (Retainability) Teenuse Terviklikus (Integrity) QoS parameetrid QoS parameetrid QoS parameetrid

  15. Teenusekvaliteedi aspektid (3) • Iga teenuse jaoks oma nõuded • QoS profiil • Erinevad teenusekvaliteedi tasemed vastavalt nõuetele

  16. Introduction • Coexistence of heterogeneous networks • Home networks, WLAN, 2G/3G, Campus-wide, satellite, … • The development of multimode handsets is a major challenge • Currently discussed standards fall short • Tomorrow user’s will expect the technology structure to “disappear” and be of no concern • Network architecture designed by IST project Daidalos • Provide seamless services accessible anytime anywhere across heterogeneous technologies • Enhanced Mobile IPv6 platform for mobility and QoS • Support for optimized mobility • Integration with QoS resource management

  17. Mobile Terminal Technologies IPv6++/MIPv6/Multicast Terminal Intelligence QoS User GUI FHO CARD IIS Handover QoSC MTC IAL QoSAL MBMS TD-CDMA WLAN WiMAX UDLR DVB-T

  18. Access Router / Access Point Technologies FHO CT D&M Terminal Intelligence IPv6++/MIPv6/ PIM Network Intelligence AM QoS CARD PA MM QoSM Handover QoSAL ENC MBMS TD-CDMA WLAN WiMAX UDLR DVB-T

  19. Handover • Mobile Initiated Handover • Network Initiated Handover • Triggered • At startup • Upon losing signal • Accounts for • user preferences • candidate APs load (QoS) • signal strengths • Triggered by • Overloaded AP (QoS) • losing signal • Accounts for • signal strengths of MTs • APs load (QoS)

  20. Wi-Fi Alliance Roadmap[Amer Hassan, Microsoft, jaanuar 2005] 802.11k 802.11j 802.11e 2004 2005 2006 Q1 Q2 Q3 Q4 Baseline Security QoS Applications 802.11h+d Extended EAP SimpleConfig WMM Scheduled Access WMM Power Save CE Phase1 Public Access Voice/Wi-Fi WCC CE Phase2

  21. QoS vajadus • QoS vajadus esmases tähenduses tuleneb video ja suure edastuskiirusega (mobiilsetest) andmesessioonidest • Lõplikult kavatsetakse realiseerida standardina IEEE 802.11n, vahevariant realiseeriti standardina IEEE 802.11e, mida toetab Proximi AP-4000.

  22. 802.11e • The 802.11e is a working group charged with making changes to the MAC layer to allow for QoS (Quality of service) in WLAN • Formally: “The purpose of Task Group E is to: Enhance the current 802.11 MAC to expand support for applications with Quality of Service requirements, and in the capabilities and efficiency of the protocol.” • The standard is in a late draft (draft 13 at this time) form and expected to be rectified this year. • Implements two main methods of QoS control • Extended DCF – also implemented as WMM • HCF – Hybrid Coordination function – uses PCF functions and only available as part of the final 802.11e spec

  23. 802.11e EDCF/WMM queues • WMM is an interim spec on the way to 802.11e implementing only eDCF • EDCF is based on using different contention parameters (CW) to differentiate queues • WMM has 4 priority levels and queues: • Audio/real time • Video • Best effort • Background • EDCF will support 8 priority levels but still 4 queues

  24. Roadmap – WLAN

  25. Link http://www.lr.ttu.ee/~avots/Introduction_to_IPv6.ppt

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